Want to Live Longer? Our Complicated Relationship to Longevity

JO STOYTE is an immensely rich Californian who enjoys all that money can buy. Of course, Jo is mortal — but he sees no reason why this, too, cannot be fixed with a little investment. He equips a laboratory and hires “a brilliant scientist” to research the secrets of everlasting life. After a surprising breakthrough, the future looks promising. But there is a sting in the tail of Stoyte’s quest for immortality, and things end badly.

Such is the plot of Aldous Huxley’s savagely funny novel After Many a Summer Dies the Swan, first published in 1939. In the 21st century, the study of aging is rapidly becoming one of the hottest frontiers in the life sciences, and Jo Stoyte’s present-day counterparts are scrambling to realize his dreams. Among a slew of new businesses founded to combat aging is Calico LLC, short for California Life Company, established in 2013 by Google Inc. and biochemist-entrepreneur Arthur D. Levinson. The US National Institute on Aging is also a key player, as are researchers in private and publicly funded organizations around the world. They are competing to extend healthy human life not just into triple digits but, possibly, into the “forever” range.

Before addressing the likelihood or soundness of such an enterprise, it’s worth noting that extending life is not just about clever biologists finding miracle cures. Life extension has already been happening — thanks, for instance, to innovations in civil engineering, which enabled reliable sewerage and clean drinking water; the development of vaccines to combat life-threatening infections; and the discovery of penicillin and other antibiotics, which virtually won the war against wholesale premature death. As a result, in richer countries, the average length of a human life has doubled over the course of the last two centuries — from 40 to 80, or thereabouts. The inhabitants of poorer nations are also adding years. While this general trend certainly brings unprecedented societal challenges, it is just as surely one of civilization’s greatest triumphs.

After the discovery of antibiotics, rich nations saw little reason to anticipate additional reductions in premature death rates. The assumption, since Biblical times, was that we would all simply grow old as we approached the traditional end of a human life — at around “three score years and ten.” But we were in for quite a surprise: life expectancy failed to hit the expected ceiling in the 1980s. In fact, it continued to increase exactly as before — at a rate of two or more years per decade. This continuing increase has nothing to do with the reduction in death rates at younger ages. Something new and entirely unexpected is happening: age itself is changing. Quite simply, most of us are now reaching old age in better health than did our parents and grandparents. This means that aging is not biologically fixed; it is, in a word, malleable.

We should surely welcome this malleability — and yet, as both our ancient myths and modern literary masterpieces testify, we humans have a complicated relationship to longevity. Under most circumstances, we consider life a blessing. But when it comes to extending it, we are troubled by the sneaky feeling that we’re crossing a moral line, playing Faust or Prometheus. Woe will betide us. How else can we interpret the bitter twist at the end of Aldous Huxley’s novel? To craft his tale, Huxley drew on the latest research on the science of aging, which was then a discipline in its infancy. He interwove observations on the indefinite longevity of certain fish with two theories. The first was that gut bacteria have a powerful effect on health (yes, this one was prescient!), and the second — that a crucial step in human evolution was a process of “neoteny,” that is, of forestalling body development, so that an adult Homo sapiens is, in effect, a modified form of immature ape.

Stoyte’s search for longevity leads him from California to England, where he discovers that someone has beaten him to his goal. Hidden from sight in a secret cellar, the Fifth Earl of Gonister is still alive at 200, but sadly changed. In neotenic terms, he has “grown up.” The once blue silk ribbon, which signalled that the wearer was a member of the distinguished royal Order of the Garter, hangs against the matted red hair of a fully mature chimpanzee.

Huxley is far from alone in suggesting that life extension is likely to come at a cost. The Struldbrugs of Luggnagg in Jonathan Swift’s classic Gulliver’s Travels are immortals who lack the gift of eternal youth; they lead miserable lives and suffer the infirmities of old age ad infinitum. Huxley himself took his novel’s title from Tennyson’s poem “Tithonus,” a figure from Greek myth. Tithonus’ lover, the goddess Eos — known to the Romans as Aurora — requests that Tithonus be blessed with eternal life, but she carelessly forgets to ask for eternal youth as well. Tithonus lives forever, but in Homer’s version “loathsome old age pressed full upon him.” In the end, the poor shriveled Tithonus turns into a cicada — eternally alive, but begging for death.

How can we overcome our niggling suspicion that there is something dubious, if not outright wrong, about wanting to live longer, healthier lives? And how might we pursue longer lives without at the same time falling prey to quasiscientific hype announcing imminent breakthroughs?

In order to understand why aging is changing, and what this means for our futures, we need to learn more about the aging process itself. As a biologist who specializes in aging, I have spent more than four decades on a quest to do exactly this. Not only have I asked why aging should occur at all (my answer is encapsulated in a concept called the “disposable soma” theory), but I have also sought to understand the fastest-growing segment of the population — those aged 85 and above.

The disposable soma theory argues that, for animals in their wild environments — including humans in historical populations — longevity is limited mostly by deaths from accidents, starvation, and diseases. In such environments, natural selection has no reason to prioritize the biologically expensive processes of bodily maintenance — at least not beyond a level that keeps organisms in reasonable shape for as long as they might, on average, survive. This is exactly what happens in humans — our bodies (soma) stay in serviceable shape until around age 40, after which the gradual buildup of faults in our cells and organs leads to the progressive decline that is the aging process.

Yet, as I have said, this aging process is malleable, susceptible to factors that can accelerate it — like stress or smoking — and those that can decelerate it by boosting our natural repair systems — like healthy nutrition, exercise, positivity.

To find out more about factors that can influence our individual health trajectories across ever-lengthening lives, my colleagues and I began, in 2006, the remarkable adventure of the still ongoing “Newcastle 85+ Study,” an extremely detailed investigation of the complex medical, biological, and social factors that can affect a person’s journey into the outer reaches of longevity. The plan was simple: we invited everyone living in Newcastle-upon-Tyne who had been born in 1921 to undergo a very comprehensive assessment, and most of them (around a thousand) agreed to do so.

For each individual, we determined whether they had any of 18 age-related conditions (e.g., arthritis, heart disease, and so on). Sadly, not one of our 85-year-olds was free of such illnesses. Indeed, three quarters of them had four or more diseases simultaneously. Yet, when asked to self-rate their health, an astonishing 78 percent — nearly four out of five — responded “good,” “very good,” or “excellent.” This was not what we had expected. The fact that these individuals had so many age-related illnesses fit, of course, with the popular perception of the very old as sadly compromised. But the corollary to this perception — that in advanced old age life becomes a burden, both to the individuals themselves and to others — was completely overturned. Here were hundreds of old people, of all social classes and backgrounds, enjoying life to the fullest, and apparently not oppressed by their many ailments. When we held a lunch party about four years into the study, to which all were invited, the room was abuzz with vitality. To be sure, some in the study were less fortunate — felled by dementia, or needing 24-hour care — but they were the exceptions.

Another part of our research looked at disability. We recorded whether each individual could or couldn’t perform each of 17 activities of daily living — shopping, cooking, driving, bathing, and so on. The results were even more unexpected. At age 85, around 20 percent could do it all, living fully independent lives, and most had only minor limitations. Even the senior health experts on the team were surprised, in part because, in their profession, they were so used to working with those in need of more serious aid and treatment. The bottom line is that everyone is an individual, even when very old. Shifts in perspective over the course of one’s life may mean that health issues that seem deeply undesirable when we are young can be successfully managed when the time comes. How often do young people say, “Please let me die before I grow old”? The secret — known to most of those who have actually walked the walk — is that old age can be okay.

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The challenges inherent in understanding and tackling the many dimensions of aging are reflected in a clutch of new books on the topic. Are these books worth reading? Yes and no. They take on questions like: Can we expect increases in human longevity to continue? Can we speed them up? And, on the personal level, what can we do to make our own lives longer and healthier? If nothing else, these books and their varied approaches reveal how little we actually know.

Spring Chicken: Stay Young Forever (or Die Trying), a popular science book by veteran journalist Bill Gifford, offers a delightfully informative tour of the highways and byways of aging research. He describes everything from historically quaint attempts to find rejuvenation through concoctions of crushed dog testicles to the latest research in molecular biology, as well as his visits to many leading US researchers and experiences as a volunteer subject in experimental investigations like the Baltimore Longitudinal Study of Aging, the world’s longest-running study of its kind.

The book is warm, often funny, and at times deeply perceptive. Some of the best passages chronicle the simple daily battles people wage against weight gain and inertia in order to better face their lengthening futures. “[D]eath is a long way from surrendering anytime soon,” Gifford writes with commendable honesty. “Until then, I’m doing everything I can to keep myself from falling apart […] But the truth is that there is no such thing as a ‘cure’ for aging, much less a ‘secret’ (as I had to explain to practically every single one of my friends while working on this book).” Many more books are likely to be written in this vein. This one does not try to do more than it can. It’s helpfully informative, and, unlike the following book, it does not go out on any outrageous limbs.

The Telomerase Revolution, by Michigan State professor of clinical medicine Michael Fossel, is narrowly focused in its advocacy of one particular hypothesis: the telomere theory of aging. Important in cancer, aging, and many other diseases, telomeres are the protective tips at the ends of chromosomes that keep the genome from unraveling. In 2009, Elizabeth Blackburn, Carol Greider, and Jack Szostak received the Nobel Prize in Physiology or Medicine for their discovery of how telomeres protect chromosomes and of the enzyme telomerase. But telomeres are far from being the only molecular players in the aging of our bodies. The book fails both in the narrowness of its outlook and in its unrealistic anticipation of progress. “Within the next decade,” writes Fossel, “we will more than double the healthy human lifespan.” Really? Even if telomere-based therapies could deliver a fraction of what he suggests, the clinical trials and drug approvals would take many years, to say nothing of our needing to wait well over a century to ascertain that these therapies will indeed double the healthy human lifespan. It’s hard not to put the book down after encountering so outrageously indefensible a claim. 

Cracking the Aging Code, by theoretical biologist Josh Mitteldorf and writer and ecological philosopher Dorion Sagan, is similarly dubious, albeit for different reasons. After a brief, meditative prologue by Sagan, the rest of the book is structured around Mitteldorf’s zealous affirmation that aging is genetically programmed: the body’s self-destruction is, he contends, good for the species. Yes, he acknowledges, this is regrettable for the individual, but it creates space for our kin and facilitates our collective adaptation to a changing environment. This idea is hardly new; the great German naturalist August Weismann advanced it as the first scientific explanation for aging back in the 1880s. It may well have the appeal of a noble sacrifice, but, as a general explanation for why aging occurs, it doesn’t hold water. Far from working to destroy us, our bodies are programmed for survival; they are simply not programmed well enough to survive indefinitely. Mitteldorf admits that he has struggled to get his ideas into the scientific mainstream. He dedicates the book to his mother, whose advice he quotes: “Go over the heads of the scientists […] take your case directly to the people.” But science is not like fashion or politics. There is no substitute for having scientific peers test the soundness of one’s work. Yes, the process can be frustrating, and yes, it sometimes takes time to chip away at conventional “wisdom.” All of us scientists have encountered such resistance and carry the scars. But in the end, it is the only way to make reliable progress. For all the liveliness of its style, and despite the fun of taking a swing at accepted views, there is much that I would take issue with in Cracking the Aging Code.

Another recent publication, Aging: The Longevity Dividend, is a different kind of book altogether. Delving deeply and expertly into biology and medicine, it is edited by three senior scholars of aging science. Sixteen articles address topics as varied as the aging of the heart, the genetic differences that predispose some among us to live to 100 or more, the importance of physical activity in combating frailty, and how our DNA becomes damaged through everyday biochemical processes taking place deep within our cells. Three additional articles boldly take on the societal implications of delayed aging. The first, by S. Jay Olshansky, one of the book’s editors, rightly laments the fact that “exaggerated claims and unproven interventions […] reach the marketplace before they are fully evaluated […]” These “have tarnished the public perception of aging science as a legitimate public health endeavour,” as have religious opposition, worry about excessive population growth, and the misguided fear that delayed aging means increased infirmity. Olshansky does an important job in raising such concerns, even if he cannot yet dispatch them.

The second article on social consequences, by USC researcher Dana Goldman, probes the likely economic consequences of forestalling aging. He models, for instance, adjustments to retirement benefits and healthcare provisions that might ensue under particular scenarios. These are weighty and politically sensitive issues, especially if the analysis were extended, as it is not here, to allow for the marked disparity across the socioeconomic spectrum — what others, including the World Health Organization, have termed the “social gradient” in health and life expectancy. On average, the “haves” live substantially longer and healthier lives than the “have-nots,” even in well-off countries where all residents have equal access to medical care. Even if one is not motivated to correct such glaring social inequity on the grounds of distributive justice, it is worth reflecting on how much more productive our societies might become, and how much less burdened by the costs of caring for those prematurely disabled, if we could find cost-effective ways to lessen the gradient.

The third societal analysis — by demographers and policy analysts Hiram Beltrán-Sánchez and Samir Soneji and gerontologist Eileen M. Crimmins — addresses the all-important question of whether the extra years we have recently gained are of good, or even acceptable, health, rather than years of illness and disability. The article concedes that, as yet, the answer is far from clear. The fundamental difficulty is in measuring the health span. It is easy enough to know whether a person is alive or dead, and the official statistics on life expectancy are correspondingly precise. But it is much harder to find reliable data on states of health. Furthermore, if we want to know whether the health span has increased faster or slower than the lifespan, we require baseline data on the states of health in earlier periods, but no such data is available. Given the importance of this question, which assumes added urgency when we consider worrying trends in health risk factors such as obesity, it is worth equipping ourselves to answer it more reliably.

Indeed, all three essays soberly call for more and better data. More work obviously needs to be done before we have a clear sense of possibilities and perils. To be sure, neither Huxley’s vision of a glissade into full-blown “ape-hood,” nor indeed “a cicada” or a fatal “sting” of some sort, is likely to punish our attempts to extend life, but this doesn’t mean we can throw caution to the wind. It could very well be that longer life will come at some cost; after all, if the disposable soma theory is correct, then the ultimate reason for aging is that it would have been too expensive, in biological terms, to build a body that could last forever. As for my stake in the enterprise, I began investigating aging when I was in my early 20s — well before I had any sense of my own body aging. Quite simply, I was curious. What is this mysterious process, and why does it occur? Everything else in biology seems to be about making things work as well as they can, so how is it that aging destroys us? Now that I am growing older myself, my research helps me understand my own body and reinforces the drive to live healthily — to eat lightly and take exercise — though not at the cost of eliminating life’s pleasures. For all that I have learned about aging, my curiosity remains unabated. Indeed, it has grown stronger, partly because as science discovers more about the process, it reveals that there is ever more to learn, ever greater complexity to unravel, and partly because I am now my own subject: through new physical and psychological experiences in myself, I learn more about what older age is really like. I know all too well that the next phase of my life will bring unwelcome changes, and of course it must end badly. But the participants of the Newcastle 85+ Study have shown me that the journey will not be without interest.

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Tom Kirkwood divides his time between Newcastle University’s Institute for Aging and the University of Copenhagen’s Center for Healthy Aging. He wrote the award-winning Time of Our Lives: The Science of Human Aging and gave the BBC Reith Lectures on The End of Age.